This is a note to let you know that I've just added the patch titled
tcp: Fix crash in TCP Fast Open
to the 3.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
tcp-fix-crash-in-tcp-fast-open.patch
and it can be found in the queue-3.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From ben@xxxxxxxxxxxxxxx Fri Apr 17 11:41:49 2015
From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Date: Wed, 15 Apr 2015 19:00:32 +0100
Subject: tcp: Fix crash in TCP Fast Open
To: stable <stable@xxxxxxxxxxxxxxx>
Cc: netdev <netdev@xxxxxxxxxxxxxxx>, Eric Dumazet <eric.dumazet@xxxxxxxxx>, 782515@xxxxxxxxxxxxxxx
Message-ID: <1429120832.3211.91.camel@xxxxxxxxxxxxxxx>
From: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Commit 355a901e6cf1 ("tcp: make connect() mem charging friendly")
changed tcp_send_syn_data() to perform an open-coded copy of the 'syn'
skb rather than using skb_copy_expand().
The open-coded copy does not cover the skb_shared_info::gso_segs
field, so in the new skb it is left set to 0. When this commit was
backported into stable branches between 3.10.y and 3.16.7-ckty
inclusive, it triggered the BUG() in tcp_transmit_skb().
Since Linux 3.18 the GSO segment count is kept in the
tcp_skb_cb::tcp_gso_segs field and tcp_send_syn_data() does copy the
tcp_skb_cb structure to the new skb, so mainline and newer stable
branches are not affected.
Set skb_shared_info::gso_segs to the correct value of 1.
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
Acked-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv4/tcp_output.c | 1 +
1 file changed, 1 insertion(+)
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -2909,6 +2909,7 @@ static int tcp_send_syn_data(struct sock
goto fallback;
syn_data->ip_summed = CHECKSUM_PARTIAL;
memcpy(syn_data->cb, syn->cb, sizeof(syn->cb));
+ skb_shinfo(syn_data)->gso_segs = 1;
if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space),
fo->data->msg_iov, 0, space))) {
kfree_skb(syn_data);
Patches currently in stable-queue which might be from ben@xxxxxxxxxxxxxxx are
queue-3.10/tcp-fix-crash-in-tcp-fast-open.patch
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